Katyn massacre

The Katyn massacre occurred from April to May 1940 as the Soviet NKVD secret police carried out a series of mass executions targeting Polish nationals during World War II. NKVD chief Lavrentiy Beria secured Soviet dictator Joseph Stalin's approval to execute all captive Polish Army officers captured during the 1939 invasion of Poland on 5 March 1940, and Polish police officers, intelligence agents, gendarmes, landowners, saboteurs, factory owners, lawyers, officials, priests, and members of the intelligentsia were also targeted. Around 22,000 Poles (including 8,000 officers) were massacred by the NKVD in the Katyn forest and at the Kalinin and Kharkiv prisons, and the German Wehrmacht discovered their mass graves in 1943 while advancing into the USSR. In 1990, the Soviet government finally admitted that it was responsible for the massacre, having blamed the Germans since the discovery of the graves.